Authors:T. Efremova, I. Leonova, V. Arbuzova, and L. Laikova
Two monosomic alien substitution lines (MAS lines, 2n=41=40+5R) of wheat
L. cv. ‘Saratovskaya 29’ were used as recipients in the development of inter-varietal substitution lines for chromosomes 5A and 5D. In the MAS lines, chromosomes 5A or 5D of ‘Saratovskaya 29’ were replaced by homoeologous univalent chromosome 5R of rye
L. cv. ‘Onokhoiskaya’, which bears the
marker gene coding for hairy peduncle. The donors included 18 spring and winter wheat varieties. The MAS lines were developed by crossing monosomic lines of ‘Saratovskaya 29’ for chromosomes 5A and 5D to a wheat-rye substitution line of ‘Saratovskaya 29’ 5R(5D) followed by cytological and morphological selection of plants with chromosome configuration 20II +5RI in metaphase I of pollen mother cells from F
plants with slightly hairy peduncles. It was shown that MAS lines could be maintained during long-term propagation (18 generations). Use of MAS lines with the
marker gene allows acceleration and abbreviation of cytological analysis and elimination of the probability of ‘univalent switch’ in the course of the development of substitution lines. The method was applied to the development of 22 ‘Saratovskaya 29’ lines with inter-varietal substitution for chromosomes 5A and 5D. Fourteen and thirteen microsatellite markers located in chromosomes 5A and 5D, respectively, were used to prove the authenticity of the inter-varietal substitution lines. According to these markers, 21 substitution lines from 22 studied were correct.
The analysis of polymorphism between 46 maize inbred lines with known genetic background and the classification of these lines in related groups was carried out by means of morphological, isoenzyme and genetic markers. The degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses. Nevertheless, on the basis of RAPD and SSR markers, all the lines could be distinguished from each other. Grouping lines into related groups it was found that, while the individual marker systems only partially reflected the actual relationships, a joint analysis of genetic markers and morphological data revealed a close correlation between the groups formed on the dendrogram and genetic backgrounds.
Authors:E. Nagy, I. Timár, Z. Hegyi, T. Spitkó, and L. Marton
The chemical composition of maize makes it suitable for a wide range of nonconventional uses, including utilisation as a new source of energy for the 21st century as a raw material for biofuel. The aim of the experiments was to amalgamate the application of genetic markers with conventional breeding methods to produce maize hybrids whose starch content and ecostability satisfied the demands of industrial use, while having yield potential and agronomic traits on a par with those of hybrids currently cultivated. The chemical quality of 220 lines was evaluated using the NIR spectrometric technique, and the five maize inbred lines with the lowest and highest starch contents were selected for genetic marker studies. The variety identification of the lines was carried out using the isoenzymes stipulated by UPOV. The following SSR (simple sequences repeat) markers were tested: phi 095, umc 1057, nc 004, phi 096, nc 007, umc 1564, phi 85, y1 SSR, umc 1178, nc 009, phi 070, umc 1066, umc 1741, umc 1069, phi 033, phi 061, wx, phi 032, phi 084 and phi 062. The analysis of the fragment patterns revealed three SSR markers that appeared to be correlated with the starch content of the maize lines. These were the primer pairs
y1 SSR, umc 1069
. These results are only of a preliminary nature, however, as the incorporation of starch is probably regulated by several genes, and the studies suggest it is also influenced by several environmental factors. It also appears likely that the bioethanol yield is determined not only by the starch content, but also by other parameters. Further research should thus be expanded to include investigations into the structural and fermentability traits of starch molecules, including the characterisation of these traits using genetic markers.
The guidelines elaborated by the Community Plant Variety Office (CPVO) of the European Union for the registration and patenting of varieties and hybrids of cultivated crops are based on the triple criteria of distinctiveness, uniformity and stability (DUS). For many species, however, morphological descriptions are not sufficient for the detection of differences between varieties. Techniques that allow varieties to be identified and distinguished precisely and reliably are essential not only for variety identification, but also to protect variety ownership rights. Biochemical and molecular genetic methods have now reached a level of development that makes them suitable for this purpose, and when these are combined with conventional field observations the breeding stock can be unequivocally identified and any existing genetic diversity can be detected. The regular application of such analyses is a fundamental criterion in the case of maize, as more and more closely related hybrids are being entered for testing.The aim of the present work was to examine how isoenzyme patterns and PCR-based genetic markers could be used in polymorphism analysis, in order to obtain information on the genetic diversity of Hungarian breeding materials. The emphasis was on finding genetic markers characteristic of individual maize varieties, rather than of maize as a species.
The use of genetic markers allows the study of polymorphism and genetic distances between maize lines in greater depth than can be achieved on the basis of phenotype and DUS traits. The analysis of polymorphism between 46 maize inbred lines with known genetic background and the classification of these lines in related groups was carried out by means of morphological description, isoenzyme analysis, RAPD analysis, and identification using gene-linked microsatellite (SSR) markers. The genetic distance or degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses; the 46 lines formed only 18 gel electrophoresis groups. Nevertheless, on the basis of RAPD and SSR markers, all the lines could be distinguished from each other. This was reflected by the PIC (polymorphism index content) values, which ranged from 0.04 to 0.55 (mean 0.27) for the various enzyme loci, while far higher values were obtained for RAPD and SSR markers (0.20–0.91, mean 0.61, and 0.54–0.90, mean 0.73, respectively). Due to the large number of lines, two lines, derived from each other or from common parents, were chosen from each related group as the basis for grouping the lines according to genetic background. It was found that, while the individual marker systems only partially reflected the actual relationships between the lines, a joint processing of the genetic markers, supplemented with morphological data, revealed a close correlation between the groups formed on the dendrogram and the genetic background.
Authors:E. Nagy, G. Gyulai, Z. Szabó, Z. Hegyi, and L. C. Marton
Williams, J. G. K., Kubelik, A. R., Rafalski, K. J., Tingey, S. V. 1990: DNA polymorphisms amplified by arbitrary primers are useful as geneticmarkers. Nucleic Acids Res. , 18 , 6531-6535.
DNA polymorphisms amplified by
Authors:Khaled Masmoudi, Ahmed Rebai, and Radhouane Ellouz
Bread wheat (
L.) is an economically and nutritionally important cereal crop in the Mediterranean region. Characterization of wheat germplasm by means of DNA fingerprinting techniques provides a tool to assess genetic diversity and to identify varieties. In this study, six Tunisian bread wheat cultivars were characterized by AFLP and SSR markers. Five AFLP primer pairs showed clear different patterns and seems to be the most suitable for analysis of the bread wheat varieties. Three SSR primers were polymorphic with more than two alleles. The pairwise genetic similarities (GS) based on these molecular markers were calculated and used to construct a dendrogram that allowed the discrimination of the six cultivars. The GS among the six varieties ranged from 0.79 to 0.36. The six varieties used in this work clustered into four groups using either AFLP or SSR markers. A high GS was found between Tebecca and Vaga Varieties which have a similar pedigree.
Authors:A. Sudaric, M. Vrataric, I. Rajcan, T. Duvnjak, and M. Volenik
The rate of genetic gain in the quantity and quality of soybean grain depends considerably on the genetic diversity of the selected parental components. Genetic diversity assessment is a crucial aspect of breeding that maximizes genetic improvement. The objectives of this study were to evaluate the genetic diversity of the selected soybean germplasm using genetic markers, as well as to compare the effectiveness of breeding procedures with and without the use of genetic markers in parental selection. The genetic relationships within the selected soybean germplasm were estimated using 14 simple sequence repeats (SSRs). The agronomic performance (grain yield, protein and oil content in the grain) of the parental components and derived lines was determined in field trials. Based on SSR marker data and phenotypic data, an association was found between the agronomic performance of the derived lines and the genetic distance between the parental lines. Crosses between more diverse parents resulted in derived lines with greater values for grain yield and grain quality compared with the parents than crosses between similar parents. The results indicated the usefulness of genetic marker information in parental selection, contributing to breeding efficiency.
Authors:Magdalena Łój, Magdalena Garncarz, and Michał Jank
The most common causes of heart failure in dogs are valvular disease, predominantly endocardiosis, and myocardial disease, predominantly dilated cardiomyopathy. They are related to changes in the expression of several genes in the heart muscle and in peripheral blood nuclear cells which could be considered as prognostic or diagnostic markers of heart disease in dogs. Since many human genetic markers of heart failure have turned out to be useless in dogs, the screening for genomic markers of canine heart failure could give more insight into the molecular pathology of these diseases and aid the development of new treatment strategies.
Authors:Mitja Križman, Jernej Jakše, Mirko Prošek, Dea Baričevič, and Branka Javornik
Agarose gel electrophoresis is a basic separation tool used in molecular biology, mostly for qualitative DNA analysis. There are constraints limiting its use in quantitative analysis, namely low repeatability and a narrow linear range. However, by using an internal standard or internal normalization, repeatability and linear range could be significantly improved. In the work discussed in this paper it was shown that an approximately fivefold improvement in repeatability and an over threefold wider linear range could be achieved by applying internal normalization. Using the proposed approach, genetic markers, for example RAPD and PCR-RFLP, or even microsatellite markers, could be conveniently quantitatively assessed using agarose gel electrophoresis.